3 files changed, 32 insertions, 37 deletions
diff --git a/src/Text/Hakyll/Internal/Render.hs b/src/Text/Hakyll/Internal/Render.hs
index 739db7a..5432f4d 100644
--- a/src/Text/Hakyll/Internal/Render.hs
+++ b/src/Text/Hakyll/Internal/Render.hs
@@ -10,7 +10,6 @@ module Text.Hakyll.Internal.Render
 import qualified Data.Map as M
 import Control.Monad.Reader (liftIO)
 import Data.Maybe (fromMaybe)
-import System.IO (hPutStrLn, stderr)
 
 import Text.Hakyll.Context (Context, ContextManipulation)
 import Text.Hakyll.File
@@ -42,6 +41,4 @@ writePage = createRenderAction $ \initialContext -> do
     destination <- toDestination url
     makeDirectories destination
     -- Substitute $root here, just before writing.
-    liftIO $ do
-        writeFile destination $ finalSubstitute (fromString body) context
-        hPutStrLn stderr $ "Writing " ++ destination
+    liftIO $ writeFile destination $ finalSubstitute (fromString body) context
diff --git a/src/Text/Hakyll/Render.hs b/src/Text/Hakyll/Render.hs
index ef7493c..3c62fe2 100644
--- a/src/Text/Hakyll/Render.hs
+++ b/src/Text/Hakyll/Render.hs
@@ -1,8 +1,7 @@
 -- | Module containing rendering functions. All these functions are used to
 --   render files to the @_site@ directory.
 module Text.Hakyll.Render 
-    ( depends
-    , render
+    ( render
     , renderWith
     , renderAndConcat
     , renderAndConcatWith
@@ -12,7 +11,6 @@ module Text.Hakyll.Render
     , css
     ) where
 
-import Control.Monad (unless)
 import Control.Arrow ((>>>))
 import Control.Monad.Reader (liftIO)
 import System.Directory (copyFile)
@@ -27,16 +25,6 @@ import Text.Hakyll.Internal.CompressCss
 import Text.Hakyll.Internal.Render
 import Text.Hakyll.Internal.Template (readTemplate)
 
--- | Execute an IO action only when the cache is invalid.
-depends :: FilePath   -- ^ File to be rendered or created.
-        -> [FilePath] -- ^ Files the render depends on.
-        -> Hakyll ()  -- ^ Action to execute when the file is out of date.
-        -> Hakyll ()
-depends file dependencies action = do
-    destination <- toDestination file
-    valid <- isFileMoreRecent destination dependencies
-    unless valid action
-
 -- | Render to a Page.
 render :: FilePath                     -- ^ Template to use for rendering.
        -> RenderAction Context Context -- ^ The render computation.
@@ -113,7 +101,7 @@ renderChainWith :: ContextManipulation
                 -> RenderAction () Context
                 -> Hakyll ()
 renderChainWith manipulation templatePaths initial =
-    runRenderAction renderChainWith'
+    runRenderActionIfNeeded renderChainWith'
   where
     renderChainWith' :: RenderAction () ()
     renderChainWith' = initial >>> manipulationAction >>> chain' >>> writePage
@@ -125,30 +113,18 @@ renderChainWith manipulation templatePaths initial =
 -- | Mark a certain file as static, so it will just be copied when the site is
 --   generated.
 static :: FilePath -> Hakyll ()
-static source = runRenderAction static'
+static source = runRenderActionIfNeeded static'
   where
-    static' = RenderAction
-        { actionDependencies = [source]
-        , actionUrl          = Just $ return source
-        , actionFunction     = actionFunction'
-        }
-
-    actionFunction' _ = do
+    static' = createFileRenderAction source $ do
         destination <- toDestination source
         makeDirectories destination
         liftIO $ copyFile source destination
 
 -- | Render a css file, compressing it.
 css :: FilePath -> Hakyll ()
-css source = runRenderAction css'
+css source = runRenderActionIfNeeded css'
   where
-    css' = RenderAction
-        { actionDependencies = [source]
-        , actionUrl          = Just $ return source
-        , actionFunction     = actionFunction'
-        }
-
-    actionFunction' _ = do
+    css' = createFileRenderAction source $ do
         contents <- liftIO $ readFile source
         destination <- toDestination source
         makeDirectories destination
diff --git a/src/Text/Hakyll/RenderAction.hs b/src/Text/Hakyll/RenderAction.hs
index 9fb9477..b84a3c5 100644
--- a/src/Text/Hakyll/RenderAction.hs
+++ b/src/Text/Hakyll/RenderAction.hs
@@ -2,17 +2,22 @@ module Text.Hakyll.RenderAction
     ( RenderAction (..)
     , createRenderAction
     , createSimpleRenderAction
+    , createFileRenderAction
     , createManipulationAction
     , chain
     , runRenderAction
+    , runRenderActionIfNeeded
     ) where
 
-import Prelude hiding ((.), id)
 import Control.Category
-import Control.Monad ((<=<), mplus)
+import Control.Monad ((<=<), mplus, unless)
+import Control.Monad.Reader (liftIO)
+import Prelude hiding ((.), id)
+import System.IO (hPutStrLn, stderr)
 
-import Text.Hakyll.Hakyll
 import Text.Hakyll.Context
+import Text.Hakyll.File (toDestination, isFileMoreRecent)
+import Text.Hakyll.Hakyll
 
 data RenderAction a b = RenderAction
     { actionDependencies :: [FilePath]
@@ -26,6 +31,13 @@ createRenderAction f = id { actionFunction = f }
 createSimpleRenderAction :: Hakyll b -> RenderAction () b
 createSimpleRenderAction = createRenderAction . const
 
+createFileRenderAction :: FilePath -> Hakyll b -> RenderAction () b
+createFileRenderAction path action = RenderAction
+    { actionDependencies = [path]
+    , actionUrl          = Just $ return path
+    , actionFunction     = const action
+    }
+
 instance Category RenderAction where
     id = RenderAction
         { actionDependencies = []
@@ -47,3 +59,13 @@ chain = foldl1 (>>>)
 
 runRenderAction :: RenderAction () a -> Hakyll a
 runRenderAction action = actionFunction action ()
+
+runRenderActionIfNeeded :: RenderAction () () -> Hakyll ()
+runRenderActionIfNeeded action = do
+    url <- case actionUrl action of
+        (Just u) -> u
+        Nothing  -> error "No url when checking dependencies."
+    destination <- toDestination url
+    valid <- isFileMoreRecent destination $ actionDependencies action
+    unless valid $ do liftIO $ hPutStrLn stderr $ "Rendering " ++ destination
+                      runRenderAction action